14 August 2014

Roland Ngom, Claudia Blais, Louis Rochette, Pierre Gosselin

GREEN SPACES FOR THE PRIMARY PREVENTION OF CARDIOVASCULAR DISEASES (CVD)

CVD = High cost for public health budgets

CVD and related public health budgets = Probably aggravated by climate change (extreme heat, pollution)

GS can be used at best advantaged in a primary prevention process

GREEN SPACES (GS) FOR THE PRIMARY PREVENTION OF CARDIOVASCULAR DISEASES (CVD)

Do GS significantly contribute to the reduction of the morbidity and mortality of CVD ?

Complex question to answer given the variety of factors related with CVD and the multiple functions of GS

THE DEFINITION OF A GS ALMOST PHILOSOPHICALWhat is a green space? Is it an open area with or without vegetation? Lawn or ligneous vegetation? Is a GS tailored for recreation? Is it a natural space? Is it a protected area? What minimal surface does a GS must have? Figure 1 : Various types of spaces

qualified as « green spaces »

RELATIONSHIP BETWEEN GS AND CVD INVESTIGATED FOR THE CENSUS METROPOLITAN AREAS (CMA) OF MONTREAL AND QUEBEC

Figure 2 : The Census Metropolitan Areas of Montreal (B) and Quebec City (A) with 6 digits postal codes

DATA AND ANALYSISMultiples GS functions with the presence of vegetation

Figure 3 : GS functions

DATA AND ANALYSISDependant variables Social Environmental

AgeGenderDeprivation indexPopulation densityImmigrationFitness centers

PollutionUrban Heat IndexAir conditionning

Covariables

Morbidity from types 1 and 2 diabetes and hypertension

Morbidity and mortality of cerebrovascular illnesses, heart failure and ischemic heart diseases.

Retrospective cohorts for three periods of exposition:P1 = 1996-2000; P2 = 2001-2005 and P3 = 2006-2011

Comparing the first quartile of distances to GS (Individuls that are nearest to GS) to the last quartile of distance GSfor each of the GS function and for each period (P1, P2 and P3)

Modèle B

Modèle A

Modèle A

Modèle B

DATA AND ANALYSISRegression models with stratified distances to GS

RESULTS AND DISCUSSIONGS with specific functions exclusively showed a significant statistical relationship with CVD in the most recent period (2006-2011):

Mortality for all the CVD = 10% and mortality from heart failures = 13% higher for the most distant (compared to the less distant) to GS that contain biking/walking trails

Morbidity from diabetes = 11% and morbidity from cerebrovascular illnesses = 13% higher for the most distant (compared to the less distant) to GS having sports facilities.

GS that stimulate physical activities

The surface area of GS was not a significant factor

RESULTS AND DISCUSSIONUnlike the CMA of Montreal, the CMA of Québec showed greater equity in access to GS

Figure 4: Significant reduction of distances between individuals and GS

RESULTS AND DISCUSSIONUnlike the CMA of Montreal, the CMA of Québec showed greater equity in access to GS

Figure 5: Margins from the Anova models of distances to green spaces, according to the categories of densities, material deprivation and by age groups

RESULTS AND DISCUSSIONA probable gentrification phenomenon

Figure 6: Regressions between individuals aged of 75 years and more and population densities according to material deprivation in the CMA of Quebec (A) and Montreal (B) for 2006- 2011

CONCLUSIONThere is an effective potential for primary prevention of CVD trough GS, however its effectiveness greatly depends on the spatial distribution of those GS and their function rather than the surface area of GS per individual.

Social and economic processes such as gentrification in urban settings greatly affect the equity in access to GS, and therefore limit the effectiveness of positive effects of GS on population health.

Urban sustainability: There is a big challenge mostly for big cities since they have to cope with multiple functions of GS (ecological and social) and with established urban structures that usually result from uncontrolled socioeconomic processes

Thanks for your attentionRemerciements à Véronique Bouzaglou pour

sa contribution dans la collecte des données, à Louis Rochette et Abdous Kacem pour leur disponibilité, à Danielle Saint-Laurent et à toutel’équipe de l’unité scientifique, Surveillance des maladies chroniques et de leurs déterminants à Institut national de santé publique du Québec pour leur assistance.

For any correspondance please contact Dr. Roland Ngomroland_pierre.ngom@ete.inrs.ca